Teenage pair caught on film kicking a pensioner in the head

GERMAN police have arrested a teenage girl and her boyfriend after a video of them kicking a pensioner in the face as he sat in an armchair emerged online.

The young woman, 17, and her 20-year-old boyfriend admitted to attacking the man in his home, a police spokesman told the Bild newspaper. He added that the pensioner had since recovered from the attack.

Thought to have been drunk at the time, the pair relentlessly attacked the 72-year-old after an argument escalated. In the video the teenager can be heard telling the man not to "hit back".

"The incident happened a few months ago," said the spokesman. But the video was uploaded to Facebook on Sunday and since then has gone viral on German-speaking social media -triggering hundreds of tip offs to the Salzgitter police, in eastern Germany.

Warning: some viewers may find the following footage distressing

It is not clear who the pensioner is but police did say they believed he was known by his attackers, who have been charged with bodily harm.

Bild newspaper spoke with the mother of the young man in the video, who said that he was taken to rehabilitation centre on Monday. "He went off the rails after his older brother at the end of 2012," she added.

The investigation continues and will, the police spokesman said, reveal whether there was a third person involved who filmed the attack.